Opposed piston diesel engines



y 8, 1962 P. JACKSON 3,033,184

OPPOSED PISTON DIESEL ENGINES Filed April 22, 1959 5 Sheets-Sheet 1 May8, 1962 P. JACKSON OPPOSED PISTON DIESEL ENGINES 5 Sheets-Sheet 2 E'iledApril 22, 1959 Illlnlllllllll G s fllltllllllill'ffll 5 May 8, 1962 P.JACKSON OPPOSED PISTON DIESEL ENGINES Filed April 22, 1959 3Sheets-Sheet 3 40 37 5 34 H I 35 6 35 3/ 25 L250 32 E $1 j 20 l6 43 W DE55 United States Patent 3,033,184 OPPOSED PISTON DIESEL ENGINES PercyJackson, Sunderland, England, assignor to William Doxford & Sons(Engineers) Limited, Sunderland, England, a British company Filed Apr.22, 1959, Ser. No. 808,120 Claims. (Cl. 123-65) The invention relates totwo-stroke cycle opposed piston diesel engines of the kind having anupright cylinder (or several such cylinders) in which both pistons workand in which both pistons are connected to a single crankshaft below theengine cylinder, the upper piston being attached to a cross-beam abovethe cylinder which is connected to the crankshaft by rods attached tothe ends of the beam. The well known Doxford engine is one example ofthis kind of engine.

Engines of the above kind are commonly provided with reciprocatingpumps, driven by the engine, for supplying air for scavenging. It is anobject of the present invention to provide such an engine with animproved construction and arrangement of engine-driven air pump.

The invention provides an engine of the above kind having a.reciprocatory scavenge-air pump mounted on top of the engine cylinder,and preferably a piunp on each of them when there are more than one, thepump having a piston which is attached directly or indirectly (e.g.through the beam) to the upper engine piston for movement therewith anda cylinder aligned with the engine cylinder and arranged to receivewithin its compass the beam during at least a part of the strokethereof.

The pump, or pumps may be single-acting.

In one construction according to the invention the pump cylinder andpiston are of rectangular form whereby the cylinder may be arranged toaccommodate the beam without being of larger volume than is required toprovide the necessary volume of air. For example one pair of sides ofthe cylinder may be slightly longer than the beam and parallel theretoand the other pair of sides may have a length less than that of thefirst pair but greater than the width of the beam.

Preferably the pump has an inlet valve in the top cover for the pumpcylinder. It is also preferred that the engine has conduits at oppositesides of the pump cylinder leading downwardly from the pump outlet to areceiver embodied in the main engine casing around the lower part of theengine cylinder. The conduits may be cast or welded integral with theframe structure and they may lead from a pump outlet valve in the topcover for the pump cylinder.

One specific construction of an opposed piston multicylinder engineaccording to the the invention will now be described, by way of example,and with reference to the accompanying drawings in which:

FIGURE 1 is a diagram showing the arrangement of one cylinder of theengine and the operating parts,

FIGURE 2 is a vertical section through one cylinder, and

FIGURE 3 is a section on the line 3-3 in FIGWE 2.

The several cylinders of the engine forming the subject of this exampleare of like construction and arrangement and only one cylinder with itsassociated parts will be described in detail. The cylinder, 10, isupright and has a set of inlet ports 11 near the bottom and a set ofexhaust ports 12 near the top, the two sets of ports being covered anduncovered by the two pistons 14, 15 respectively, in well known manner.The lower piston 14, has a piston rod 16, cross-head 17 and connectingrod 18 connecting the piston to one throw 19 of the crankshaft. Theupper piston, 15, is secured at its upper end to a cross-beam 20 ofwhich the ends lie outside the compass of the engine cylinder 10.Vertical coupling rods 21 are attached to the ends of the beam 20 and attheir lower ends have cross-head 22 and connecting rod connections 23 totwo further throws 24 of the crankshaft.

Secured to the top ofthe beam 20 there is a thin, platelike horizontalpump piston 28 of rectangular form. The longer sides 28a of the pistonare parallel to the length of the beam 20 and slightly longer than thebeam. The shorter sides 2811 are somewhat longer than the width of themain body of the beam. The piston works in a pump cylinder 30 ofcorresponding shape and aligned with the engine cylinder. In operationthe beam 20 enters into the pump cylinder 30 during the upper part ofthe stroke.

Vertical guideways 31 are formed centrally in the longer sides of thepump cylinder for the reception of guide slippers 32 attached to thebeam 20. The upper ends of the slippers, are in this example, level withthe top face of the pump piston 28 and so, in effect, act as smalllateral extensions from the piston to seal the guideways 31.

On top of the pump cylinder cover there is a chamber which is dividedinto two parts 34, 35 by a central vertical partition 36 which, in thisexample, is parallel to the beam 20. The part 34 has an opening 37 toatmosphere forming an air inlet and this part also has an inlet openinginto the cylinder controlled by automatic inlet valves 38. The part 35has outlet openings 39 from the cylinder controlled by automaticdischarge valves 40. The ends of the part 35 extend over two uprightducts or trunks 41 cast in the cylinder walls and leading downwardlythrough further ducts 42 integral with the main engine framework into areceiving chamber 43 formed in the entablature whence the air can passinto the engine cylinder through the inlet ports 11 when uncovered bythe lower piston.

Various modifications may be made in the construction described above.For instance the upper ends of the slippers 32 may be beneath the piston28 and the latter have ears or extensions into the guideways 31 to closethe latter. The partition 36 may extend transversely of the beam insteadof parallel thereto.

I claim:

1. In a two-stroke cycle opposed-piston diesel engine of the kind havingan upright working cylinder, an upper piston working vertically in thecylinder, a cross-beam rigidly attached to the upper piston above theworking cylinder and extending radially beyond the Working cylinder onopposite sides, two connecting rods rigidly attached one to eachextremity of the cross-beam and extending vertically downwards outsidethe working cylinder, two cross-heads attached respectively to the lowerends of the connecting rods and guide means therefor and an air pumpcylinder mounted over the top of the working cylinder, coaxialtherewith; the provision of a vertical guideway in the wall of the pumpcylinder, guide means rigidly attached to the cross-beam and engaging inthe guideway and a pump piston in the form of a substantially fiat platerigidly mounted directly on top of the cross-beam to work in the pumpcylinder.

2.. In a two-stroke cycle opposed-piston diesel engine as claimed inclaim 1 wherein the pump cylinder and pump piston are substantiallyrectangular.

3. In a two-stroke cycle opposed-piston diesel engine as claimed inclaim 1 wherein the pump cylinder has a dimension in the lengthwisedirection of the cross-beam which is greater than the length of thecross-beam and the cross-beam enters the pump cylinder during at leastpart of the piston stroke.

4. In a two-stroke cycle opposed-piston diesel engine as claimed inclaim 1 wherein there are strengthening ribs extending across theworking face of the pump piston.

5. In a two-stroke cycle opposed-piston diesel engine as claimed inclaim 1 wherein there is a top cover over 3 the pump cylinder an inletvalve and an outlet valve in the top cover, a chamber above the topcover communicating with the outlet valve, conduits at opposite sides ofthe pump cylinder leading downward from the chamber and a receiveraround the lower part of the working cylinder connected to the lowerends of the conduits.

References Cited in the file of this patent UNITED STATES PATENTS MaderMay 24, 1927 Junkers Aug. 7, 1928 Bronander Dec. 22, 1936 Schrom June29, 1937 Frauenfelder June 14, 1938 Maxwell Jan. 14, 1941 McLintock Nov.28, 1944 FOREIGN PATENTS Great Britain Oct. 24, 1929 Great Britain Oct.22, 1958 France Mar. 29, 1950

